1.Why is galvanized siding durable?
Core Advantages: Rust and Corrosion Prevention
Galvanized coil is a steel strip coated with zinc. This zinc first reacts with oxygen and moisture in the air to form a dense basic zinc carbonate film, protecting the steel underneath from corrosion. As long as the zinc layer is not extensively damaged, the steel inside will not rust.
This makes it much more durable than ordinary cold-rolled steel (iron sheet) wall panels, making it ideal for withstanding the elements.
Strength and Rigidity
Steel sheets inherently possess a certain strength. Rolling them into various sheet shapes (such as corrugated sheet) through a tile press further enhances their mechanical strength and wind resistance, making them ideal for wall enclosures.
Cost-Effectiveness
Galvanized coil is a basic and mature industrial material with relatively low production costs. This makes prefabricated house wall panels affordable and highly marketable.
2.How does the thickness of the zinc layer affect its durability?
This is the most critical factor. The thicker the zinc coating, the stronger its corrosion resistance and longer its lifespan. Zinc coating thickness is typically expressed in grams per square meter (g/m²).
For normal environments: galvanized coils with a total zinc coating of 60-120g/m² on both sides are sufficient.
For high humidity, coastal areas, or industrial areas: galvanized coils with a zinc coating of 120g/m² or higher, or even 180-275g/m² (Z275), are recommended for significantly enhanced corrosion resistance.
3.What are the key factors that determine its durability?
Operating Environment
Normal urban and rural environments: Durability is excellent, with normal use expected to last 5-10 years or even longer.
High humidity and coastal areas: Seaside air contains chloride ions, which accelerate corrosion of zinc and steel. In such environments, the lifespan of galvanized steel sheets is significantly shortened.
Industrial areas: The air may contain acidic gases such as sulfides and nitrogen oxides, forming acid rain, which can also corrode the zinc coating.
Processing and Installation Quality
Deep scratches or abrasions to the galvanized coating during the rolling and cutting process can damage the protective layer, leading to rust formation at the site.
Overtightening the fixing screws or improperly drilling the holes during installation can also damage the zinc coating, requiring proper sealing.
4.How does it compare with ordinary iron sheet (cold rolled sheet)?
Galvanized steel wins hands down. Iron sheet rusts easily and has a short lifespan.
5.How does it compare with color-coated steel sheets (color-coated galvanized sheets)?
Color-coated steel plates are an "upgraded version" of galvanized plates, with better durability and aesthetics, and a slightly higher price.